In this research, economic value for production traits and reproduction traits of Afshari sheep were estimated using a deterministic bio-economic model. In production system of Afshari sheep, the variable costs comprised 99 % of total costs. Revenue sources consisted of meat, milk, wool and manure, where meat with 83.4 % of revenue had the highest effect. Economic value for a trait as the change in profit of production system by increasing one unit in the trait avrage, while avrage of other traits were constant was estimated. After that, milk, wool production and ewe survival were followed. Birth weight had negative economic value. The sensitivity of economic value of various traits to ±10 % changes in feed, non- feed costs and also to meat, wool and milk prices were examined, and the results showed the economic values of wool and milk productions were not sensitive to none of the costs. Also changes in the costs of rearing and marketing had no effect on the economic value for body weight in various ages of wool and milk production. By changing the price of meat, the economic values of all traits except birth weight, wool and milk production were changed, by increasing the price of meat results to increases in the economic values of those traits. Among various factors, meat price had the most effect on the economic value of traits.

In the present study, to estimate genetic parameters and genetic and phenotypic trends in Holstein dairy cows in the north of Iran, the records from first lactation of 11398 collected from 1989 to 2006 were used. Records were collected from 290 herds. Productive traits were 305 day-2x adjusted milk and fat yield and reproductive traits were age at first calving, calving interval and dry days. Genetic parameters were estimated by univariate and bivariate animal model using ASREML software. Estimated heritabilities for 305 day-2x milk, fat, age at first calving, calving interval and dry days gathered from univariate analysis were 0.27 (±0.02), 0.19 (±0.02), 0.1 (± 0.02), 0.03 (±0.01) and 0.1 (±0.02) respectively. Genetic correlation between milk and fat yield was 0.82. Genetic correlations of milk and fat production with age at first calving were -0.2 and -0.23 and with calving interval were 0.31 and 0.40, respectively. Genetic trends for milk and fat yield were 2.8 (±0.4) and 0.05 (±0.01) kg/year and for age at calving, calving interval and dry days were -0.28 (±0.01), 0.02 (±0.002) and -0.03 (±0.004) days/year, respectively. Phenotypic trends for these traits were 113.24 (kg/year), 2.3 (kg/year), -2.66 (days/year), 0.37 (days/year) and -0.36 (days/year). Based on unfavorable genetic correlations between productive and reproductive traits, using a selection index including both of these traits is necessary for Holstein dairy cows.

Calving records from April 1996 to December 2005 comprising 31863 calving events of 1173 dairy cows in a large commercial dairy herd were used to evaluate the effects of heat stress, using temperature-humidity index (THI) on milk yield and composition and reproductive performance of Holstein dairy cows under humid climatic conditions of Rasht in Iran. THI values were grouped into six groups: 30-40 (THI1), 41-50 (THI2), 51-60 (THI3), 61-70 (THI4), 71-80 (THI5) and 81-90 (THI6). Dairy cows in THI6 had lower milk and fat yields than other groups of THI, but cows in THI1 and THI2 had the greatest amounts of milk and fat yields, respectively (P<0.05). However, dairy cows in the second group of THI had lower percentages of fat than the sixth group of THI (P<0.05). Spring-calved cows had longer days open than cows calved in other seasons (P<0.05). Also, summer-calved cows had greater number of services per conception and lower conception rates than cows calved in other seasons (P<0.05). Dairy cows within the THI5 which calved in spring and/or calving years 2004-2005 had the longest days open (P<0.05). Cows in the second group of THI had the greatest and the lowest number of inseminations and conception rates compared with other groups of THI, respectively. The results of the present study indicated that summer heat stress negatively affected milk yield and composition and reproductive performance of dairy cows. Therefore, application of management interventions to ameliorate the effects of heat load on the performance of dairy cows could be needed in certain periods of the year under the climatic conditions.

The productive traits including body weight at different ages, carcass related-traits and reproductive traits including egg production, mean egg weight, fertility and hatchability were studied in a population of Japanese quail in the Research Center of Gorgan University of Agricultural Sciences and Natural Resources. The fixed effects for body weight were sex and generation-hatch, for carcass related-traits were sex and hatch and for reproductive traits was hatch effect. Descriptive statistics, including the test for normality and significance of fix effects, were obtained using the univariate and general linear model (GLM) procedures of SAS. The mean values of body weight at hatching, 7, 14, 21, 28, 35, 42 and 91 days of age were 8.91, 32.26, 72.56, 124.5, 171.38, 203.34, 232.37 and 270.6 g, respectively. The average percentages of carcass, breast muscle, thigh muscle, skin, abdominal fat and intramuscular fat were 59.12, 24.12, 14.51, 5.2, 0.8 and 8%, respectively. Also average values of age and weight at sexual maturity were 48.32 days and 244.12 g, respectively. The significant differences (P<0.05) were observed between various levels of fixed effects for studied traits. Although the mean values of body weight and weight of carcass composition in females were higher than males, percentage of carcass composition in females were lower than males (P<0.05).

In this study, total numbers of 4817, 1913, 1515, 6249, 1871, 1532, 1208 records of birth weight, weight of 3 and 12 month age, cashmere weight, total number of lambs born, total number of lambs weaned and lambing interval in Raienian Cashmere goat were used. These records were collected in Baft station from 1989 to 2006. The animal model was used for genetic evaluation and estimation of genetic and phenotypic correlations for these traits. Heritability above was estimated 0.24, 0.07, 0.20, 0.17, 0.06, 0.08 and 0.03, respectively on the basis of the best model for each trait. Genetic correlation between birth weight and12 month weight, birth weight and cashmere weight, 3month weight and total number of lambs weaned, 3month weight and total number of lambs born, 12 month weight and cashmere weight, 12month weight and total number of lambs born, 12 month weight and total number of lams weaned, 12month weight and lambing interval, lambing interval and total number of lambs born, lambing interval and total number of lambs weaned, was estimated 0.27, 0.072, 0.02, -0.16, 0.28, 0.10, -0.27, -0.12, 0.30 and 0.42, respectively and phenotypic correlation was estimated 0.23, 0.056, 0.066, 0.07, 0.20, 0.01, -0.54 , -0.43, 0.02 and 0.04 respectively, using Bivariate analysis.

Metritis as one of the substantial disorder is one of the major diseases in dairy farm. The purpose of this study was to evaluate the detrimental effects of metritis on a dairy farm complex in Guilan province. Data from years 2000 to 2004 was analyzed using logistic regression procedure. In this research, rate of metritis during the study period was 19.99%. Results indicated that year and herd significantly affected the incidence of metritis (P<0.01). This rate was highest in year 2002 and for the herd of number 1. The sex and season had not significant effects on the incidence of metritis (P>0.05). Also metritis had a significant effect on mean milk yield by five months after parturition (P<0.01). The average milk yield in dairy cows that affected by metritis and cows without metritis were 20.73 and 21.76 kg, respectively. Furthermore, metritis had a significant effect on some of the reproductive parameters (P<0.01) and the average of days open in the cows with metritis was 17.82 day greater than the cows without metritis. Also, the average of interval from calving to first insemination was 6.33 days greater than cows without metritis. Metritis had not significant effect on services per conception (P>0.05). It is concluded that effects of herd and year on metritis and effects of metritis on mean milk yield and days open were effective.

The purpose of this project is to investigate the characteristics of birth weight, three-month weight, weight gain from birth to three months, maturity weight and milk production of female goats during the years 2018 to 2022 in Kerman province, related to native goats (BB) and their hybrids with the Saanen breed, respectively,with 50 (S1 B), 75 (S2B) and 87.5 (S3B) percent of the Saanen breed gene. A number of 9 herds selected in Kerman province. The total number of female goats were 2089, of which 1909 were fertile and 2584 goats were born. Data storage, editing, and preparation were performed using Excel 2013 software. After editing and preparing the recorded information, the effect of fixed factors on variables and data analysis was performed using the Spss software. Birth weight, milk weight, and daily weight gain from birth to milk intake in crossbred kids were higher than in purebred kids. Crossbred goats had a higher milk production weight than native goats. In native goats, a fertility rate of 85% was obtained, while in those inseminated with Saanen breed, the fertility rate was 92%. The weaning rate in those inseminated with Saanen breed was higher than in native goats (137% vs. 111%). Also, the reproductive ability in those inseminated with Saanen breed was higher.

Introduction: Cattle are a monotocous species meaning that, under most circumstances, a successful pregnancy results in the birth of one calf. Twinning rate has been reported in dairy cows from 3 to 5 percent, which can be influenced by maternal age. The birth of twins is detrimental to the majority of beef and dairy cattle producer. Financial loss arising from any of twinning has been reported in Europe between 109 to 201 dollars in recent years. Because it is associated with undesirable consequences such as reduced survival, calf, cow increased removal rate and poor performance. This also reduces pregnancy rates and profitability herds. One of the effects of twinning severe is reduction of the number of calves for replacement fertility in dairy cows. This is a loss arising from an increase in infant mortality and a gender bias in bull calves homo zygote. Twinning rate increases significantly the incidence of reproductive abnormalities, including the retained placenta, dystocia, stillbirth and abortion. Many studies have been done on the effect of multiple pregnancies in cattle production and reproduction. Higher milk production for cows twin issue is controversial as some studies have shown that there is a positive correlation between the rate of twinning in dairy cattle and milk production. But in the next lactation, production for cows that have been the twin of the infected cow metabolic disease in the previous period was lower. In a study reported that cows spend fewer days in the twin peak production. The results of the study on the effect of twinning on reproductive traits of Holstein cows-Farzin showed that only half of the twin cows are prone to reproduce in the next period. It is also reported a greater number of insemination per conception in twin compared to single cows. In addition, it has been reported that the twin was more than 15 days from calving to first services. Average twin cows experiencing 1.7 times more death and removal in lifetime production than cows single. The aim of this study was to estimate the rate of twinning in Iranian Holstein dairy cows and the estimated effect on production traits and reproductive twinning....